Heights Community School parents have filed a lawsuit that is now moving to federal courts against the St. Paul Public School District in Minnesota, amid an investigation into allegations that teacher Timothy Olmsted discriminated against black students.

Olmsted resigned after the district placed him on paid leave in the spring after parents complained that he called black students "fat, black and stupid" and told them, "you will never amount to anything" and "you only have one parent.

The teacher also allegedly forced black students to sit in the back of the classroom, or sit with their desks facing the wall.

"He told the whole entire class that it is easier for him to teach rich white folks than poor black people," Tolbert told reporters.

Olmsted resigned in March, but is still being paid through the first week of October, and parents are dissatisfied. He is also not facing disciplinary action due to the resignation.

In the suit, parents claim that the district failed to protect their children from Olmsted, the Star Tribune reports. Latasha Tolbert, mother of 12-year-old Jamia Ware, said she made nearly 100 calls to school officials in the fall regarding Olmsted's classroom behavior, but the no one acted until January.

District representatives, however, tell the Star Tribune that an investigation was launched promptly and all complaints against the teacher were addressed immediately. Olmsted's attorney notes that the teacher "denies any improper conduct and believes that the claims against him are baseless."

But the educator has a record of controversy. The St. Paul School District reported in 2002 that Olmsted gave a sixth grade girl a birthday card with sexual innuendos, and requested that she read it to the class. He was also accused of giving a graphic description of castrating horses and throwing testicles into a field to feed cats.

For the various incidents over the years, disciplinary actions against him have ranged from written reprimands to days of suspension without pay. Students also find his more recent, racial comments strange.

"He would say random things like when I get out of the shower my dog dries me off," student Aylecia Ingram-Jones told reporters in a separate report.

Her father, Miguel Jones, has moved the teen to another school district, and asserts that there should be no question about whether Olmsted should be allowed to keep teaching.

"I wouldn't stand for it," Jones said. "Right is right. Wrong is wrong."

Minnesota does not have statewide regulations regarding disciplinary action for teachers, so process is followed based on district decisions and as outlined in teachers' union contracts.

The allegations in St. Paul are similar to complaints against Kathleen Pyles, a math teacher at North End Middle School in Waterbury, Conn., who was placed on paid leave in June while officials investigate claims that she addressed a black student with a racist remark.

Parents have accused Pyles of inappropriately calling a student "black boy" when she couldn't remember his name. When she first called the boy by the wrong name, he pointed out her mistake. So she responded, "How about black boy? Go sit down, black boy."

Parents are calling for her dismissal.

In another incident in March, a Virginia high school English teacher allegedly asked the only black student in the class to read a poem in a "blacker" manner.

Jordan Shumate, a ninth-grader at George C. Marshall High School in Falls Church, Va., says he was reading aloud Langston Hughes' "Ballad of the Landlord" when teacher Marilyn Bart interrupted him.

"She told me, 'Blacker, Jordan -- c'mon, blacker. I thought you were black,'" Shumate told The Washington Post.